Film for thermal imaging

Abstract

Film suitable for thermal imaging comprising (1) a substrate formed from a flexible material, (2) a layer of thermally imageable material applied to at least one major surface of the substrate, and (3) a release coating overlying the layer of imageable material, the release coating being the hydrosilation product of (a) a polyorganohydrosiloxane, (b) an ethylenically-unsaturated perfluoropolyether monomer, and (c) an effective amount of a hydrosilation catalyst. Preferably, the film is transparent to visible light. The coating is sufficiently flexible so that the film bearing it can be imaged in commercially available infrared copying machines. Toner powder from plain paper copies will not stick to this coating when the imaging film is processed in a conventional thermal imaging apparatus.

What is claimed is: 
     
       1. Thermally imageable film comprising a substrate, a layer of thermally imageable material applied to at least one major surface of said substrate, and a release coating overlying the layer of imageable material, said release coating being the hydroxilation product of (a) a polyorganohydrosiloxane, (b) an ethylenically-unsaturated perfluoroether monomer, and (c) an effective amount of a hydrosilation catalyst. 
     
     
       2. The film of claim 1 wherein said release coating is the reaction product of (1) a polyorganohydrosiloxane comprising at least two hydrogen toms attached to a silicon atom or atoms, with no more than two hydrogen atoms being on any one silicon atom, and having a number average molecular weight of from 106 to about 50,000;   (2) an ethylenically-unsaturated perfluoro-polyether monomer having segments comprising a plurality of repeating units of the formula --C a  F 2a  O--, in which "a" in each unit is independently an interger of 1 to 4, and at least one ethylenically-unsaturated group, and   (3) an effective amount of a hydrosilation catalyst for brining about the condensation of the polyorganohydrosiloxane and the ethylenically-unsaturated perfluoropolyether monomer.   
     
     
       3. The film of claim 2 wherein said polyorganohydrosiloxane comprises from about 2 to about 35 weight percent of the release coating composition and said ethylenically-unsaturated perfluoropolyether comprises from about 65 to about 98 weight percent of the release coating composition. 
     
     
       4. The film of claim 1 wherein said film is transparent to visible light. 
     
     
       5. The film of claim 1 wherein the substrate is polymeric film. 
     
     
       6. The film of claim 3 wherein said polymeric film substrate is polyethylene terephthalate. 
     
     
       7. The film of claim 1 wherein the imageable material comprises a binder, nitrate salt, and at least one leuco dye. 
     
     
       8. Method of preparing a transparency by means of a thermal imaging process comprising the steps of (a) contacting an image-bearing original with the film of claim 4,   (b) applying thermal energy to the original whereby the original image wise absorbs said thermal energy and transfers said thermal energy to the transparent film to form a copy of the image of the original on the transparent film, and   (c) separating said original from said transparent film.